1. Field of the Invention
The present invention relates to a chemical cleaning solution for gas turbine blades. In particular, the present invention relates to a cleaning composition comprising a glycol alkyl ether compound, a solvent and a metal corrosion inhibitor component.
2. Description of the Prior Art
Industrial gas turbine engines are used worldwide. An example of a gas turbine is a Mars Gas Turbine or a Taurus 70 Gas Turbine, manufactured by Solar Turbines, Inc. A Mars turbine has a 15 stage compressor and each stage is comprised of a stationary row of blades (stator blades) and a rotating row of blades. The blades are the largest at stage 1 and the smallest at stage 15. During operation, air is drawn into the compressor's divergent passage and compressed through every stage.
The stator blades direct the compressed air at each stage across its companion row of rotating blades. The air foil of the stator and rotating blades has been designed for maximum efficiency. However, as a result of continuous operation, contaminants build up on the leading edge of these air foils. Consequently, overall efficiency is lost in the compressor section. This in turn reduces the horsepower available for consumer use. The Mars turbine engine compresses approximately 90 pounds per second of air at full rated horsepower. There is only a small amount of airborne contaminants per standard cubic foot of air. However, with the massive amounts of air passing through the turbine, these contaminants are multiplied. Moreover, the air enters the turbine at room temperature and leaves the compressor at approximately 630° F. Most of the lost efficiency is across the first three or four stages, and it is very difficult to clean the blades once the contaminants have adhered to them.
Accordingly, gas turbines must be cleaned, usually monthly, to maintain operating efficiency and maximum available horsepower. There are two main ways to clean a gas turbine; one method is crank washing, and the other is on-line washing. Crank washing is the more common of the two. During cleaning, each turbine uses about 2 gallons of cleaner to clean the turbine, and an additional 1–2 gallons to clean the package. The same cleaner may also be used for general cleaning purposes in the operating plant. Accordingly, there exists a large need for a superior gas turbine cleaner.
Gas turbine crank washing is a method whereby a cleaning solution is introduced into the turbine compressor inlet of a turbine while slow cranking takes place. This slow cranking occurs cold without ignition or fuel being introduced. There are many types of turbine compressor cleaners on the market. These include Penetone® 19, by Penetone Corporation; Connect® 5000, by Conntect, Inc.; Turco® 6783 Series, by Turco Products, Inc.; ZOK® 27, by ZOK Incorporated; and Fyrewash®, by Rochem Corporation.
However, current cleaning products have several disadvantages. These disadvantages include excessive foaming, extended soaking periods, low water solubility, and residual cleaner. Current products cure some of these disadvantages; however, none have been able to cure all of these properties.